gnm-plugin.h contains the following entry:
#include <tools/gnm-solver.h>
The problem is that with the latest makefile changes gnm-solver.h is no longer being installed into tools subdir. This causes issues like

gnm-plugin.h contains the following entry:
#include <tools/gnm-solver.h>
The problem is that with the latest makefile changes gnm-solver.h is no longer being installed into tools subdir. This causes issues like